//===================================================================================
// Microsoft patterns & practices
// Composite Application Guidance for Windows Presentation Foundation and Silverlight
//===================================================================================
// Copyright (c) Microsoft Corporation.  All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===================================================================================
// The example companies, organizations, products, domain names,
// e-mail addresses, logos, people, places, and events depicted
// herein are fictitious.  No association with any real company,
// organization, product, domain name, email address, logo, person,
// places, or events is intended or should be inferred.
//===================================================================================
using System;
using System.Collections.Generic;
using System.Linq;

namespace Microsoft.Practices.Prism.Events
{
	internal class WeakDelegatesManager
	{
		private readonly List<DelegateReference> listeners = new List<DelegateReference>();

		public void AddListener(Delegate listener)
		{
			this.listeners.Add(new DelegateReference(listener, false));
		}

		public void RemoveListener(Delegate listener)
		{
			this.listeners.RemoveAll(reference =>
			{
				//Remove the listener, and prune collected listeners
				Delegate target = reference.Target;
				return listener.Equals(target) || target == null;
			});
		}

		public void Raise(params object[] args)
		{
			this.listeners.RemoveAll(listener => listener.Target == null);

			foreach (Delegate handler in this.listeners.ToList().Select(listener => listener.Target).Where(listener => listener != null))
			{
				handler.DynamicInvoke(args);
			}
		}
	}
}